Control valves are designed to operate at a specific fluid pressure, flow rate, or other condition to protect elements of the system from pressure, flow rate, or other fluid condition that exceeds the design limits thereof. When a condition that exceeds the design limits is sensed, a pilot valve directs a main control valve to either open or close, partially or fully, to alleviate the conditions therein. Such use of pilot valves to direct main control valves is well known in the prior art. U.S. Pat. Nos. 6,945,507, 5,520,366, and 4,615,354 are exemplary of pilot valves incorporating the features of the prior art.
Pilot valves are typically smaller valves than the main control valves and can be separate from or integral with the main control valves. The pilot valves are designed to sense a specific condition and guide the main control valve. The main control valve may operate by opening or closing to control the specific condition. This is done to protect components from excessive pressure or flow rate, or other conditions that exceed the limitation of components or of the fluid itself. This includes, but is not limited to the controlling of vacuum, differential pressure, contaminant levels, and mixing of different fluids.
The main control valve must respond quickly to the sensed fluid condition to protect the elements of the system. Fast response time in a main control valve requires the related pilot valve to be able to respond quickly. The longer the response time of the pilot valve, the longer the undesirable fluid condition will be maintained within the system.
It would be desirable to have a pilot valve for guiding a main control valve, wherein a response time of the pilot valve is minimized.